Electrical connection



P. K. TURNER V ELECTRICAL CONNECTION May 4, 1965 y 4, 1965 P. K. TURNER 3,182,282

ELECTRICAL CONNECTION Filed Oct. 29, 1962 2 Sheets-Sheet 2 //7 1/81? 2901": Prascat' KTu/wa;

United States Patent M 3,182,282 ELECTRICAL CONNECTION Prescott K. Turner, Fairfield, Conn, assignor to General Electric Company, a corporation of New York Filed Oct. 29, 1962, Ser. No. 233,756 14) Claims. (Cl. 339-97) The present invention relates to crimped electrical connections and particularly to an electrical connector which can be crimped to an insulated conductor to provide a permanent and mechanically strong electrically conductive connection therebetween.

To commercially manufacture nearly all kinds of electrical apparatus and wiring circuits, it is necessary to electrically connect the ends of wires or insulated conductors to some other electrical conducting element, such as a terminal connector. One form of prior art connection which has seen widespread usefor electrically connecting a wire to a terminal connector involves the use of solderless connectors which are compressed or crimped onto the bare wire of an insulated conductor from which the insulation has been removed in a prior operation. Another form of prior art connection'utilizes a portion of the terminal connector to pierce through the insulation of the insulated conductor in order to make electrical connection to the wire portion thereof. This latter form of terminal connector has the advantage of not requiring the prior removal of insulation to permit the making of the electrical connection. In prior art forms of insulation piercing terminal connectors, the cold fiow characteristics of commonly used wire insulation materials (such as, for example, poly-vinyl chloride) have reduced the electrical efficiency of the connection. More specifically, the cold flow characteristics of these insulative materials have resulted in the ultimate reduction of pressure forces between the terminal connector and the wire of the conductor, thereby increasing the resistance of the electrical joint and limiting the value of electrical current for which the terminal connector is suitable. For certain types of electrical apparatus, it is very important that these crimped terminal connectors be fastened to their associated conductors in such a manner that a secure electrical and mechanical connection is achieved which is capable of withstanding severe wear and tear and rigorous day to day usage. The present invention contemplates an improved crimped electrical connection which effectively satisfies such requirements of secure electrical and mechanical connection.

An important object of the present invention is to provide a new and improved crimped electrical connection which has an enhanced reliability.

It is another object of the present invention to provide an improved connection which is achieved by the novel cooperation between a terminal connector and an insulated conductor, and. affords an excellent electrical contact with high mechanical strength.

It is another object of my invention to provide an improved terminal connector which can be applied to insulated electrical conductors without the need for prior removal of the insulation from the conductor.

It is another object of my invention to provide an improved insulation pierce type of terminal connector of relatively high current carrying capacity.

A further object of my invention is to provide an improved terminal connection for an insulated conductor, which connection is of simplified construction and may be very economically manufactured.

In carrying out my invention, in one form thereof, I have provided an improved electrical and mechanical connection for a terminal connector and an insulated electrical conductor. The connector includes a contact portion for electrical engagement with a mating contact 3,182,282 ?atenterl May 4, 1965 of another wiring device, and a conductor accommodating portion for electrical and mechanical attachment to the insulated end of the conductor. The conductor receiving portion includes a series of spaced apart parallel pairs of opposed fingers curled over toward each other to form a ferrule. This ferrule includes a series of transverse gaps disposed respectively between adjacent pairs of the opposed fingers. With such an arrangement, the insulated end of the conductor is positioned in the conductor accommodating portion of the conductor and the fingers thereof are crimped into insulation piercing engagement with the conductor to establish an electrical contact. When the fingers are crimped into engagement with the insulated conductor the gaps between the fingers allow the relief flow of insulation outwardly therefrom. This relief flow of conductor insulation is in the form of transverse sections of insulation which bulge outwardly from the gaps. The transverse bulging of the insulation from the gaps allows a very efiicient electrical connection to be formed between the terminal connector and theconductor. Such a connection has a very high current carrying capacity, improved dimensional and electrical stability over a long period of time and a secure mechanical joint.

Further aspects of my invention will become apparent hereinafter and the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which I regard as my invention. The invention, however, as to organization and method of utilization, together with further objects and advan tages thereof, may best be understood by reference to the following description, when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view showing an improved connector contact blade connected to a conductor in accordance with one form of the present invention;

FIG. 2 is a front elevational view of the contact blade of FIG. 1;

FIG. 3 is a side elevation view, partially in section, of the contact blade of FIG. 1;

FIG. 4 is a rear elevational view of the contact blade of FIG. 1;

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 4;

FIG. 6 is a bottom view of the contact blade of FIG. 1;

FIG. 7 is a fragmentary View showing the mode of cooperation between the conductor accommodating portion of the contact blade and its associated conductor end;

FIG. 8 is a sectional view taken along the line S-8 of FIG. 7;

FIG. 9 is a fragmentary sectional view taken generally along the line 9-9 of FIG. 7;

FIG. 10 is a bottom view of a connector contact blade embodying an alternate form of my invention;

FIG. 11 is a fragmentary sectional view of the contact blade of FIG. 10 connected to a conductor;

FIG. 12 is a side elevation view partially in section and partially broken away, of a connector plug which includes the contact blades shown in FIG. 1; and

FIG. 13 is a fragmentary front elevation view of the connector plug of FIG. 12.

Referring first to FIGS. 1-4 and 12 of the drawings, there is illustrated an electrical contact blade 1 for use in a connector plug 2. The plug 2 in which the contact blade 1 embodying my invention is to be incorporated may be of the molded-on type, and for such a construction the electrical connections between the contact blades 1 and their associated conductor 3 would be made prior to the molding operation.

The improved contact blade 1 is formed from a very thin sheet of conductive metal, such as, for example,

brass having a thickness in the order of 0.015 inch. As shown by FIGS. 24, the contact blade 1 constitutes a two-ply or folded-over type of rigid construction, which in its physical dimensions, accurately conforms to the dimensional requirements of the Underwriters Laboratories, Inc. More particularly, blade 1 is manufactured by folding over and shaping a contact portion 4 of a thin strip of conductive metal, as shown in FIG. 5, to form longitudinally extending curved sides 5 and abutting curved inner ends 7 (on one side thereof). As illustrated in FIGS. 25, the contact portion 4 of blade 1 thus includes two separate elongated coplanar contact surfaces 10 on one side thereof (FIG. 4), and another contact surface 11 (FIG. 2) on the other side thereof opposite surfaces 1%). To provide a detent means for the blade 1, a transverse embossrnent or bump 9 is shaped outwardly from the surface 11 of the conductive strip which underlies the curved inner ends 7 (as shown in FIGS. 2 and 5). Embossment 9 projects perpendicularly outwardly from the plane of surface 11 of the blade 1 and extends transversely to the longitudinal axis of the blade. As shown in FIG. 2, the embossment 9 is also located in the center of the strip between the curved sides 5, and extends generally parallel to the outer end 13. (See also FIG. 4.)

To provide an elongated area of contact thickness for the contact blade 1, on surface 11 thereof, portion 4 includes an elongated plateau 15. Plateau provides a uniform contact thickness for each blade and permits a maximum contact pressure to be realized over an elongated longitudinal contact area when the blade is inserted into engagement with a female contact (not shown) of an appropriate receptacle or power outlet. In addition, the plateau 15 serves as a strengthening means for the contact portion 4 of the blade 1.

To enable the contact blade 1 to be readily interlocked into secure engagement with molded insulating material 14 of the plug 2, as shown in FIGS. 2, 3 and 12, a

swaged eyelet 16 is formed in contact portion 4. The eyelet 16 includes a round hole 16a surrounded by a peripheral rim 16b of rigid construction. Rim 16b projects perpendicularly outwa-rdlyfrom the plane of surface 11, as shown in FIG. 13. The insulating material 14 is molded around the lower-portion of blade 1, as shown in FIGS. 12 and 13, and section 1411 of this material extends through the hole 16a and rim 16b. The portion 14a of the insulating material 14 which extends through the eyelet 16 and the engagement of the outer peripheral surface of rim 16b with the molded material 14 serves to provide a very compact structure for enhancing the pullstrength of the contact blade 1 with respect to the plug body. Such an arrangement thus provides a very secure mechanical interengagement between the blade 1 and plug 2.

Turning now to an important aspect of the present invention whereby an improved mechanical and electrical connection is achieved for a contact, such as the contact blade 1, attention is now directed to FIGS. 2, 3, 4 and 6. For attaching the two-ply contact blade 1 to an appropriate conductor 3, a cord accommodating shank portion 17 extends outwardly from the contact portion 4 of the blade 1, or downwardly as shown in FIGS. 3 and 4. The shank portion 17 includes an elongated U-shaped base section 19 (FIG. 6) and a series of spaced apart pairs of opposed fingers 21a-21d which extend outwardly from the opposite sides of base section 19. The fingers 21a21d are curled over toward each other (as shown by way of example for fingers 21b in FIG. 8), to pierce the insulation of conductor 3 and form a ferrule with a transverse gap 23 disposed between each adjacent pair of fingers. Thus, for example, as shown in FIGS. 1 and 7, the opposed pair of fingers 21a are crimped over against, into and through the insulation of conductor 3, and the opposed fingers 21b are crimped over against, into and through the insulation of conductor 3, the fingers ends of each pair of crimped fingers.

21b being spaced apart from fingers 21a to provide a transverse gap 23. An important purpose of the transverse gap 23 as shall be further described hereinafter, is to provide relief or escape for the flow of conductor insulating material when the fingers 21a-2ld are crimped and pierced into the insulation of the conductor.

Turning now to a more detailed explanation of the structure and function of the insulation piercing fingers 21a-21d, attention is directed to FIG. 3. For the illustrated contact blade 1, the fingers 21a include outwardly facing concave ends 25a, the fingers 21b include outwardly facing concave ends 25b, the fingers 210 include outwardly facing concave ends 25c, and the fingers 21d include outwardly facing concave ends 25d. The lengths of the fingers 21a-21d are progressively varied as shown in FIG. 3 so that for the uncrimped blade 1 the concave end 25:: is disposed outwardly from base section 19 for a first predetermined distance, the concave end 2512 of fingers 21b is disposed outwardly from base section 19 for a lesser distance, etc. From viewing FIG. 3 of the drawing, it will thus be seen that the concave outer end 25d of fingers 21d is disposed closest to the base section 19 of the plug blade and the concave end 25a of fingers 21a is disposed furthest away from base section 19. The purpose of this dimensional arrangement of the fingers 21a-21d shall become apparent hereinafter.

To help assure an effective insulation piercing connection between blade 1 and conductor 3, on the left side or bight part of base section 19 of the blade 1, viewing FIG. 3, there are formed a series of four insulation piercing ridges or notches 27a-Z7d, respectively, which together form a corrugated surface. The ridges 27a27d are disposed in transverse alignment with respective pairs of the opposed fingers 21a-21d (FIG. 3) and they provide transversely extending projecting edges (FIG. 3) which face toward the right side of base section 19 (viewing FIG. 3) and pierce the insulation of conductor 3 to electrically engage the strands thereof underneath the (See FIG. 8.) Thus, more particularly, as shown in FIG. 9, the ridges 27a-27d project perpendicularly upwardly from the inner elongated bight sunface of base section 19 and extend transversely to the longitudinal axis of the shank portion 17. Each of the insulation piercing ridges 27a27d is also disposed underneath a pair of insulation piercing fingers 21a-21d (as illustrated in FIG. 9).

For a detailed explanation of how the fingers 21a-21d and ridges 27a-27d of the contact blade 1 coact with the insulated conductor 3 to provide a secure and reliable connection therebetween, attention is now directed to FIGS. 1 and 7-9. The conductor 3 is fastened to the shank portion 17 of the contact blade 1 without requiring any previous removal of insulation from the end of the conductor 3 which is to be fastened to the blade, due to the insulation piercing capability of fingers 21a-21d and their opposed respective ridges 27a27d. More particularly, the insulated end of conductor 3 is connected to the shank portion 17 of contact blade 1 by means of a pair of suitably configured crimping dies (not shown). As the dies are closed into engagement with the shank portion 17 of the contact blade 1 (upon positioning the insulated end of the conductor 3 within the U-shaped base section 19 between the fingers Zia-21d) sharp cusps or ridges of one of the dies turn inwardly the opposed ends 25a25d of each pair of fingers 21a-21d, as illustrated in FIG. 8. When the concave ends 25a25d of the fingers 21a-21d are all turned inwardly, they pierce the insulation of conductor 3, as indicated in FIG. 9. In addition, as the fingers 21a-21d are crimped into compressive engagement with the conductor 3, the inner edges of ridges 27a-27d also pierce the insulation of conductor 3.

To help enable the ends 25a-25d of the fingers, and the ridges 27a-27d to effectively pierce the insulation of the conductor 3 and also at the same time provide a secure electrical and mechanical connection between the contact blade 1 and the conductor 3, during the crimping operation the transverse gaps 23 allow the relief flow of the insulation material surrounding the conductive strands, in response to the compressive forces exerted upon the fingers 21a-21d by the crimping dies. This relief fiow of the insulation material through the gaps 23 forms transverse bulges 29 of insulation between each pair of opposed fingers 21a-2ld and a spaced apart adjacent pair of these fingers. By providing a means for relief flow of the conductor insulation material in response to the crimping forces an excellent electrical connection is obtained between the blade 1 and conductor 3.

Sucha connection has very stable electrical resistancecharacteristics and a relatively high current carrying capacity; 7

As shown in FIG. 1, the bulges 29 of insulation have their long axes in a direction perpendicular to the longitudinal axis of shank portion 17, and they provide an effective means for mechanical cooperation between the conductor 3 and the contact blade 1, which achieves excellent pullout strength.

To further explain the mode of coaction in the illustrated connection between the fingers Zia-21d, the ridges 27a-27d, and the gaps 23, as shown in FIG. 9, the axes of the transverse ridges 27a27d are disposed respectively directly underneath the concave insulation piercing ends 25a25d of the fingers Zia-21d. With such an arrangement, the opposed fingers of each pair, such as for example, thefingers 21a-2'ld, are crimped into engagement with a portion of the conductor which is sandwiched between them and their underlying notch, such as for example, ridge 2711, so that their free ends pierce the insulation, which flows into the transverse gaps 23 (FIG. 7) formed between the fingers. The effect which the crimping of the fingers 21a-21d has upon the conductor 3 is similar to that of upper dies (i.e., fingers 21a-21a) acting upon lower dies (i.e., the ridges 27114711) and the conductor material which is compressed between the .fingers and ridges has a wave -shaped contour (FIG. 9)

in consonance with the configurations of the concave ends 25a-25d of the fingers and their centrally associated ridges 27a-27d. Since both the apexes of ridges 27a- 27d and as the concave ends 25a25d of the fingers, pierce the insulation to electrically engage the conductor strands (as shown in H6. 8) the conductor is intimately clamped between the fingers and their associated ridges. This pro- .vides a high quality metal-to-metal contact with very good durability and without in any way damaging the strands of the conductor during the crimping operation.

As previously set forth, the fingers 21a-21d are progressively longer between the outer end of the shank portion 17 (i.e., the lower end of sank portion 17, viewing FIG. 3) and its inner end (i.e., the upper end of shank portion 17, viewing FIG. 3). With such an arrangement, when crimping dies of uniform size (i.e., depth) are utilized for attachment of the shank portion 17 to conductor 3, as shown in FIG. 9, the concave ends 25d of finger 21d will compress the insulation and the conductive material of conductor 3 to a less extent than will the concave ends 250 of the fingers 210. In addition, the concave ends 25b of fingers 21b compress the conductive wires of conductor 3 to a greater extent than the fingers 21c but to a lesser extent that the concave ends 25a of the fingers 21a compress their underlying conductive wires. As a result of the progressively variant compression of conductor 3 by the fingers Mad id, the bulges 29 project outwardly and away from the axis of the conductor at progressively varying heights and radii of curvature. Thus, more particularly, the bulge 29 of insulation between fingers 21a and 21b has a somewhat greater height and radius of curvature than the bulge 2.9 between fingers 21b and 21c and the bulge 29 between fingers 21b and 21c has a somewhat greater radius of 6 curvature than the bulge between fingers 21c and 21d. With such a structural arrangement, the tightest connection is achieved between the shank portion 17 of the contact blade 1 and the conductor at fingers 21a (see FIG. 9). The degree of tightness with which fingers 21b engage conductor 3 is somewhat less than the degree of tightness with which fingers 21a engage the conductor. In addition, the degree of tightness with which fingers 21c engage conductor 3 is somewhat less than for fingers 21b and the degree of tightness achieved by fingers 21d (at the entry location for the conductor) is minimal when compared with fingers 21a, 21b and 210. Such an arrangement (i.e., the progressively variant tightness obtained by using insulation piercing fingers of different lengths) is desirable because it achieves an efiicient strain relief effect between the shank portion 17 of the blade and the conductor 3 where the conductor enters the contact blade, and it also conveniently lends itself to wider manufacturing flexibility by enabling the contact blade to be effectively secured to wires of variable insulation thicknesses and contact metal thicknesses. This approach also helps to compensate for other manufacturing variables involved in connecting the blade 1 to the conductor 3, such as for example the unintentional variance in crimping heights, and variances in positioning and piercing the conductor. Thus, by using insulation piercing fingers Mat-21d of progressively varying lengths and tightnesses an effective strain relief is provided at the mouth of the contact blade 1 and a very broad range of tolerances is permitted for efiectively connecting the contact blade 1 to the conductors.

FIGS. 10 and 11 represents a modified form of my invention wherein a contact blade 101 has been employed. Blade 101 is similar to blade 1, except for some variance in the structure of the insulation piercing fingers 121a- 121d. For blade 101, the component parts and sections thereof shown in FIGS. 10 and 11 which have a structural similarity to their correlative parts for blade 1, and perform the same basic functions, are identified by the same two reference numerals with the numeral 1 prefixed thereto.

The basic difference between contact blade 10-1 and contact blade 1 resides in the fact that the contact blade 1% is originally manufactured with all of its insulation piercing fingers 121a-1Zlld having the same length (FIG. 10). When shank portion 117 of the contact blade 1&1 is crimped to the insulated conductor 3, the die sections (not shown) are of nonuniform and progressively variant configuration to provide progressively different heights. Thus, as shown in FIG. ll, the fingers 121a have their upper curved surfaces pressed down from above to a greater extent than that of fingers 121b, fingers 1211: are pressed downwardly by the die to a greater extent that the fingers 121a, and the fingers 121d have their upper surfaces pressed downwardly the least amount. Transverse notches 127a127d are provided and disposed relative to curled over fingers 121a121d in the same arrangement as described above for ridges 27a27d. With this arrangement, the coaction and cooperation between the concave ends 125a125d of the respective insulation piercing fingers 121a-121d and the insulation and conductive wires of the conductor, 3 is identical to the effect achieved by the fingers Zia-21d of the contact blade 1 (i.e., in the same manner as is shown in FIG. 8). By using a die with a progressively varying height configuration together with insulation piercing fingers U la-121d of the same length, the efficient strain relieving effect and wide manufacturing flexibility for blade 101 are obtained to the same extent and in the same manner as previously described for blade 1.

It will now, therefore, be seen that my new and improved connection for a contact and conductor as illustrated herein provides for the novel and effective secure- =meut of these two members together. It will be further understood that my invention provides a simplified and efficient means for electrically and mechanically connecting a terminal connector to an insulated conductor and thereby obtaining a connection of very high current carrying capacity. The connect-ion of my invention also provides an improved dimensional and electrical stability over a long period of time, and it is very strong mechanically. A connector plug of improved overall mechanical strength has also been provided.

While in accordance with the patent statutes, 1 have described what at present are considered to be the preferred embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from my invention, and I, therefore, aim in the following claims to cover all such equivalent variations as fall within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical terminal connection for an insulated conductor and a contact, said contact comprising a portion for receiving said conductor, said conductor receiving portion including a plurality of pairs of opposed fingers and a corrugated surface with the corrugations and the fingers extending transversely to the longitudinal axis of said conductor, the fingers of each pair being curled over toward each other and over said corrugated surface to form with the corrugated surface a ferrule for gripping the conductor, the free ends of said fingers and the inner edges of the ridges of the corrugations being arranged in insulation piercing electrical engagement with said conductor, said conductor being compressed between said fingers and said corrugations, each pair of said fingers being spaced apart from an adjacent pair of said fingers by a transverse gap, with a portion of insulation from said conductor bulging outwardly by relief flow from said gap between adjacent pairs of said fingers thereby to enhance the electrical and mechanical connection between said conductor and said contact.

2. An electrical connection for securing an insulated conductor to another device, said connection comprising a contact including a portion for receiving said conductor, said portion including a plurality of spaced apart parallel fingers and a corrugated surface with the corrugations and the fingers extending transversely to the longitudinal axis of said conductor, the lengths of said fingers progressively increasing in length between one end of said conductor receiving portion and the other end of said port-ion, said fingers curled over said corrugated surface to form with the corrugated surface a ferrule for gripping the conductor, the free ends of said fingers and the inner edges of the ridges of said corrugation being arranged in insulation piercing engagement with said conductor thereby to establish electrical engagement between said contact and conductor, said fingers being crimped into engagement with said conductor with uniform heights to provide progressively increasing degrees of tightness between the one end of said conductor receiving portion and the other end thereby compressing said conductor into waves of increasing magnitude, each adjacent parallel finger being spaced apart by a gap extending therebetween in a direction transverse to the longitudinal axis of the conductor, said fingers of said conductor receiving portion of said contact being crimped into electrical and mechanical engagement with the insulated conductor so that a portion of insulation from said conductor bulges outwardly by relief flow from said gap and cooperates therewith thereby to enhance the electrical connection and strengthen the mechanical connection between said conductor and said contact, the magnitude of said bulges increasing with the increasing tightness of the engagement of the adjacent fingers "3. An electrical connection for an insulated conductor and a contact, said contact comprising a portion for receiving said conductor, said conductor receiving portion including a plurality of pairs of opposed fingers and a corrugated surface with the corrrugations and the fingers extending transversely to the longitudinal axis of said conductor, the lengths of said opposed fingers of each pair being of substantially the same length, the fingers of each pair being curled over toward each other and over said corrugated surface to form with the corrugated surface a ferrule for gripping the conductor, the free ends of said fingers and the inner edges of the ridges of said corrugations being arranged in insulation piercing engagement with said conductor thereby to establish elec trical engagement between said contact and conductor, the pair of fingers being crimped into engagement with said conductor with nonuniform heights to provide progressively increasing degrees of tightness between one end of said conductor receiving portion and the other end, each pair of said fingers being spaced apart from an adjacent pair of said fingers by a gap extending therebetween in a direction generally perpendicular to the iongitudinal axis of said conductor, said conductor receiving portion of said contact being crimped into electrical engagement with the insulated conductor with a portion of insulation from said conductor bulging outwardly by relief flow from said gap thereby to enhance the electrical and mechanical connection between said conductor and said contact.

4. An electrical connection for securing an insulated conductor to another device, said connection comprising a contact including a ferrule portion for receiving said conductor, said ferrule portion including a plurality of spaced apart pairs of opposed fingers, each pair of said fingers extending in a plane perpendicular to the longitudinal axis of said conductor, the fingers of each pair being curled over toward each other for gripping said conductor and piercing the insulation thereof, and a plurality of ridges one of which is disposed underneath the free ends of each pair of fingers and arranged in clamping association therewith for piercing the insulation of said conductor, each of said ridges extending transversely to the longitudinal axis of the conductor and being generally located in the same plane as its associated fingers, each pair of said fingers being spaced apart from an adjacent pair of said fingers by a gap extending therebetween in a plane perpendicular to the longitudinal axis of said conductor, said pairs of said fingers and their associated ridges being arranged to electrically engage said conductor by piercing the insulation thereof and coacting in compression with the conductor and said insulation so that a transverse portion of said insulation bulges outwardly from said gap by relief fiow thereby to provide a reliable and stable connection of high current carrying capacity and good mechanical strength.

5. The connection of claim 4 wherein the lengths of the opposed fingers of each pair are the same and the pairs of fingers have progressively increasing lengths between one end of said conductor receiving portion and the other end of said portion, said pairs of fingers being crimped into engagement with said conductor with uniform heights to provide progressively increasing degrees of tightness between the one end of said conductor receiving portion and the other end thereof.

6. The connection of claim 4 wherein the lengths of said fingers are substantially the same and the free ends of said pairs of fingers are crimped into compressive engagement with said conductor with nonuniform heights t2 provide progressively increasing degrees of tightness between one end of said conductor receiving portion and the other end thereof.

7. The connection of claim 4 wherein the lengths of the opposed fingers of each pair are the same and the pairs of fingers are arranged so that they pierce the insulation and engage the conductor with progressively increasing tightness between an end of said conductor receiving ferrule portion where the conductor enters said contact and the oher end of said ferrule portion.

8. An electrical connection for securing an insulated conductor to a contact, said contact comprising a conductor receiving portion, said portion including a plurality of pairs of opposed fingers, the fingers of each pair being curled over toward each other for gripping said conductor and piercing the insulation thereof, and a ridge disposed underneath each pair of fingers adjacent the free ends thereof for piercing the insulation of said conductor, each pair of said fingers being spaced apart from an adjacent pair of said fingers by a gap extending therebetween, said fingers and said ridges being arranged to pierce the insulation of said conductor for electrically engaging said conductor, said fingers each having a concave end which overlies the respective ridge when said fingers are fully curled over thereby to compress the metal in said conductor against said ridge and shape it over said ridge and said fingers and said ridges and coacting in compression with said insulation so that portions thereof bulge outwardly by relief flow from said gap thereby to provide a reliable and stable electrical connection of high current carrying capacity and mechanical strength.

9. An improved connector plug comprising a body of molded insulating material, at least one elongated contact extending outwardly from said body, each contact including a flat portion partially imbedded in said molded insulating material and a conductor receiving portion wholly embedded in said molded insulating material, and an eyelet formed in said flat portion, said eyelet having an annular lip projecting perpendicularly outwardly from the plane of said flat portion and being imbedded in said insulating material, portions of said insulating material extending through said eyelet and surrounding said lip thereby to securely anchor said contact to said insulating body, said conductor receiving portion including a plurality of pairs of opposed fingers and a corrugated surface with the corrugations and the fingers extending transversely to the longitudinal axis of said conductor, the fingers of each pair being curled over toward each other and over said corrugated surface to form with the corrugated surface a ferrule for gripping the conductor, the free ends of said fingers and the inner edges of the ridges of the corrugations being arranged in insulation piercing electrical engagement with said conductor, said conductor being compressed between said fingers and said corrugations, each pair of said fingers being spaced apart from an adjacent pair of said fingers by a transverse gap, with a portion of insulation from said conductor bulging outwardly by relief flow from said gap between adjacent pairs of said fingers thereby to enhance the electrical and mechanical connection between said conductor and said contact, portions of said plug insulation material extending into the grooves formed by the back of said ridges and in between the bulging rib portions of said conductor to further securely anchor said contact to said insulating body.

10. For use in a connector plug having a molded insulating body, a pair of elongated contact blades extending outwardly from said body in spaced parallel relationship, each of said blades including a conductor receiving portion and a flat section embedded in said molded body and With an extruded eyelet formed in said flat section, said eyelet having an annular lip projecting outwardly from the plane of said fiat section and embedded in said insulating material with portions thereof extending through said eyelet and surrounding said lip thereby to securely anchor said blade to said body, said contact blade also including a conductor receiving portion, said conductor receiving portion including a plurality of pairs of opposed fingers and a corrugated surface with the corrugations and the fingers extending transversely to the longitudinal axis of said conductor, said conductor receiving portion embedded in said body, the fingers of each pair being crimped over toward each other and over said corrugated surface to form with said corrugated surface a ferrule for gripping an insulated conductor, each pair of said fingers being spaced apart from an adjacent pair of said fingers by a gap extending therebetween in a direction generally perpendicular to the longitudinal axis of said conductor and parallel to said corrugations, said conductor receiving portion of said contact being crimped into electrical engagement with the insulated conductor with a portion of insulation from said conductor bulging outwardly by relief flow from said gap thereby to enhance the electrical and mechanical connection between said conductor and said contact.

References titted by the Examiner UNITED STATES PATENTS 1,771,635 7/30 Hubbell 339-1-95 2,062,480 12/36 Stanley 264274 X 2,063,038 12/36 Hubbell 339-62 2,205,051 6/40 Schmitt 264-274 X 2,671,205 3/54 Wermine 339-59 2,680,235 6/54 Pierce 339-97 2,694,188 11/54 Poupitch 339- 2,716,741 8/55 Ustin 339-103 2,747,171 5/56 Martines 339-276 2,982,938 5/ 61 Klumpp 339-97 FOREIGN PATENTS 1,09 8,692 8/55 France.

615,737 1/ 49 Great Britain. 67,298 2/51 Netherlands. JOSEPH D. SEERS, Primary Examiner, 

1. AN ELECTRICAL TERMINAL CONNECTION FOR AN INSULATED CONDUCTOR AND A CONTACT, SAID CONTACT COMPRISING A PORTION FOR RECEIVING SAID CONDUCTOR, SAID CONDUCTOR RECEIVEING PORTION INCLUDING A PLURALITY OF PAIRS OF OPPOSED FINGERS AND A CORRUGATED SURFACE WITH THE CORRUGATIONS AND THE FINGERS EXTENDING TRANSVERSELY TO THE LONGITUDINAL AXIS OF SAID CONDUCTOR, THE FINGERS OF EACH PAIR BEING CURLED OVER TOWARD EACH OTHER AND OVER SAID CORRUGATED SURFACE TO FORM WITH THE CORRUGATED SURFACE A FERRULE FOR GRIPPING THE CONDUCTOR, THE FREE ENDS OF SAID FINGERS AND THE INNER EDGES OF THE RIDGES OF THE CORRUGATIONS BEING ARRANGED IN INSULATION PIERCING ELECTRICAL ENGAGEMENT WITH SAID CONDUCTOR, SAID CONDUCTOR BEING COMPRESSED BETWEEN SAID FINGERS AND SAID CORRUGATIONS, EACH PAIR OF SAID FINGERS BEING SPACED APART FROM AN ADJACENT PAIR OF SAID FINGERS BY A TRANSVERSE GAP, WITH A PORTION OF INSULATION FROM SAID CONDUCTOR BULGING OUTWARDLY BY RELIEF FLOW FROM SAID GAP BETWEEN ADJACENT PAIRS OF SAID FINGERS THEREBY TO ENHANCE THE ELECTRICAL AND MECHANICAL CONNECTION BETWEEN SAID CONDUCTOR AND SAID CONTACT. 